The manufacture of BMSOC has been described in detail in U.S. Pat. No. 4,387,215 to Bailey. As described in that patent, BMSOC is used in ring-opening polymerization.
Briefly, the process of Bailey may be described as follows. Dicyclopentadiene is heated to between 240.degree.-250.degree. C. to form an 80-85% yield cyclopentadiene, which is allowed to react with acrolein to produce norbornene carboxaldehyde in a yield of 79% based on the cyclopentadiene (83% based on the acrolein). The resulting norbornene carboxaldehyde is allowed to react with formaldehyde and caustic to form 5-norbornene-2,2-dimethanol which is heated to between 420.degree.-450.degree. C. to form 1,1-dihydroxymethyl ethylene and cyclopentadiene in a yield of 10-40%. The 1,1-dihydroxymethyl ethylene, is allowed to react with dibutyl tin oxide to form a cyclic tin intermediate which is allowed to react with carbon disulfide (CS.sub.2) to form 3,9-dimethylene-1,5,7,11-tetraoxa-spiro[5,5]undecane (BMSOC).
Because the yield of the 1,1-dihydroxymethyl ethylene is so low and the pyrolysis procedure is difficult and costly on a commercial scale, and because dibutyl tin oxide is also costly, a new approach was sought. Furthermore, because Bailey's process uses acrolein which is toxic and has been declared too dangerous to ship and is mostly available only for captive use, this gave added impetus to seek a simpler, safer, less costly, more productive route to prepare BMSOC.
In search of this new process, it became evident that 1,1-dichloromethyl ethylene, already known from the literature, viz. Mooridian and Clarke, J.Am.Chem.Soc. 67, 942 (1945), would be a key intermediate in a process of manufacturing BMSOC. Unfortunately, the method of preparing 1,1-dichloromethyl ethylene described by Mooridian and Clarke involved a route which was expensive and inconvenient. Briefly, that method involved reacting pentaerythritol with thionyl chloride to form a mixture of chlorinated hydrocarbons and alcohols, one of which is trischloromethyl ethanol in a comparatively low yield. The trischloromethyl ethanol is oxidized with nitric acid to form trichloro-methyl acetic acid. The latter is converted at high temperature using quinoline to produce 1,1-dichloromethyl ethylene in low yield. This was then further converted to the corresponding diol, used by Bailey to make BMSOC. The diol was formed in very low yield by hydrolysis with lime.